This invention relates to long span conveyor systems and more particularly to an improved track section and novel hanger support assembly utilized therein.
Conventional power and free conveyor systems utilize a track structure formed by end-to-end track sections each comprising an I beam member mounted above and co-extensive with a pair of opposed channel iron members. The vertically aligned I beam and channel members are connected and spaced apart by yoke plates which are spaced along the length of the track section. The I beam member, referred to as the power rail, supports the drive trolleys and drive chain with the opposed channel members forming a track which supports the free trolleys and load-bearing carrier assemblies extending therebetween.
In a typical installation these track sections are suspended from the overlying main beams of the superstructure of the building in which the conveyor is installed. In order to comply with the specifications and standards for deflection and stress, it is usually necessary to add intermediate beams on closer centers than the main beams in order to provide intermediate support points to shorten the span. Although the specifications can be met in this manner, the addition of such intermediate support structure increases system costs and adds to the load to be borne by the original building superstructure, which often must then be reinforced in order to support the added weight.
A previous method addressing the elimination of additional superstructure has been described in U.S. Pat. No. 3,217,658. Therein is described a conveyor track section utilizing a longitudinally tapered rail cap for reinforcing the I beam power rail. Yoke plates extend through slots in the rail cap with the depending legs thereof supporting the channel-shaped members of the free trolley track therebelow. This arrangement proposes to increase the overall strength and rigidity of the track section. Although assumably effective in its function, the disclosed structural design of the rail cap requires each track section to be individually constructed so as to be suspended at its terminal ends from the overhead beams with the tapered rail cap extending therebetween. Thus the length of the section must correspond to the length of span between hanger points as defined by the location of the overhead building support beams. In turn the construction of variously-dimensioned track sections is necessary and results in increased engineering, fabrication and installation costs.
Also, it may be necessary to extend straight sections of the track beyond such hanger support points for connection to displaced vertical and/or horizontal turns of the conveyor system. Thus additional straight track sections of the above design are required which again increases system costs.
Finally, the prior methods of fastening each track section to the superior superstructure utilized an angle iron clip welded to the top of the I beam power rail and bolted to an angle iron hanger attached to the overlying superstructure. This prior method was a costly, labor-intensive one and dependent on the skill of the welder. Moreover, reliability was a problem as there was no efficient way to pretest the strength of the weld between the angle iron clip and I beam.
In response thereto, I have invented a novel track section that uses a uniform, serrated, T-shaped element as a continuous, reinforcing rail cap for the underlying power rail and free trolley track suspended therefrom. My continuous rail cap presents an upper flange member, superior to the power rail I beam, which cooperates with a novel hanger assembly so that the rail cap may be hung from the overlying superstructure at user-selectable points therealong. Moreover, the hanger assembly presents a clamp which slidably receives the upper flange member of the rail cap until tightened and thus is not welded thereto and may be easily positioned during installation of the track. Accordingly, the maximum load capacity of the hanger assembly may be readily predetermined in order to avoid the uncertainties associated with weld attachment as above-described. Therefore, a plurality of track sections of standard length utilizing my new design may be fabricated off site with the assurance that they can be used in normal subsequent installations. In turn, design, manufacture and installation costs are reduced and the overall cost effectiveness of the power and free conveyor system is thus enhanced.
It is, therefore, a general object of this invention to provide a reinforced track section for a power and free conveyor system.
Another object of this invention is to provide a track section, as aforesaid, which uses a uniform, continuously extending rail cap for reinforcement of the underlying I beam power rail and trolley track depending therefrom.
Still another object of this invention is to provide a track section, as aforesaid, in combination with a novel track hanger engaging the rail cap to suspend the track section from the overlying building superstructure at user-selectable points therealong.
Another important object of this invention is to provide a track section utilizing a hanger assembly, as aforesaid, in which the hanger slidably receives the rail cap therein until the installation is complete.
Another object of this invention is to provide a track section with hanger assembly, as aforesaid, in which the maximum load capacity of the hanger assembly is determinable before suspension of a track section therefrom.
A more particular object of this invention is to provide a rail cap, as aforesaid, which offers a uniform, uninterrupted reinforcement to the underlying track section connected thereto.
Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, an embodiment of this invention.